Bottom Line:
Here, I highlight some of the key breakthroughs in biological oceanography that have been enabled by SOs, which include areas such as trophic dynamics, understanding variability, improved biogeochemical models and the role of ocean biology in the global carbon cycle.In the near future, SOs are poised to make progress on several fronts, including detecting climate change effects on ocean biogeochemistry, high-resolution observations of physical-biological interactions and greater observational capability in both the mesopelagic zone and harsh environments, such as the Arctic.We are now entering a new era for biological SOs, one in which our motivations have evolved from the need to acquire basic understanding of the ocean's state and variability, to a need to understand ocean biogeochemistry in the context of increasing pressure in the form of climate change, overfishing and eutrophication.

ABSTRACTSustained observations (SOs) have provided invaluable information on the ocean's biology and biogeochemistry for over 50 years. They continue to play a vital role in elucidating the functioning of the marine ecosystem, particularly in the light of ongoing climate change. Repeated, consistent observations have provided the opportunity to resolve temporal and/or spatial variability in ocean biogeochemistry, which has driven exploration of the factors controlling biological parameters and processes. Here, I highlight some of the key breakthroughs in biological oceanography that have been enabled by SOs, which include areas such as trophic dynamics, understanding variability, improved biogeochemical models and the role of ocean biology in the global carbon cycle. In the near future, SOs are poised to make progress on several fronts, including detecting climate change effects on ocean biogeochemistry, high-resolution observations of physical-biological interactions and greater observational capability in both the mesopelagic zone and harsh environments, such as the Arctic. We are now entering a new era for biological SOs, one in which our motivations have evolved from the need to acquire basic understanding of the ocean's state and variability, to a need to understand ocean biogeochemistry in the context of increasing pressure in the form of climate change, overfishing and eutrophication.

RSTA20130334F1: (a) Density of in situ surface chlorophyll concentration measurements collected between 1773 and 1997, extracted from the World Ocean Database at http://www.nodc.noaa.gov/OC5/SELECT/dbsearch/dbsearch.html; data collected from time-series stations, shipboard profiles and under-way systems, and gliders. (b) In situ chlorophyll concentration from the top 10 m collected at the Hawaii Ocean Time-series site every two to four weeks between 1989 and 2012; acquired from http://hahana.soest.hawaii.edu/hot/hot-dogs/. (c) Global chlorophyll concentration (mg m−3) at 9 km spatial resolution averaged between April and June 1998 acquired by the SeaWiFS satellite; data downloaded from http://oceancolor.gsfc.nasa.gov/. (Online version in colour.)

Mentions:
In the past 30 years or so, SOs have wrought a revolution in biological oceanography. To put this into perspective, I present an example based on chlorophyll concentration. Between 1773 and 1997, chlorophyll was measured in situ at a total of approximately 300 000 stations (as reported in the World Ocean Database). Although this is a huge number of data points, inspection of the data distribution in figure 1a shows that large parts of the ocean have less than five measurements and some have none at all. Vast tracts of the Southern Ocean, for example, have zero or only one data point in the database. It would be difficult to ascertain even the broad-scale distribution of chlorophyll concentration from this dataset, and one would struggle to deduce any information on temporal variability on the large scale. The advent of regular sampling at SO locations began to reveal detailed information about the seasonal (and eventually interannual) variability in chlorophyll concentration, as shown in the example for the Hawaii Ocean Time-series site (HOT; figure 1b). Information on the temporal variability of chlorophyll allowed significant advances in our understanding of the range of variability and the physical and biological factors that control chlorophyll concentrations. However, time-series station data cannot provide any information on the spatial variability in chlorophyll, except at the largest scales (e.g. the differences between ocean basins through a comparison of HOT and the Bermuda Atlantic Time-series Study site; BATS). The arrival of satellite-derived chlorophyll data in the late 1970s prompted another revolution in biological oceanography as the dramatic spatial variability in chlorophyll on mesoscales was revealed (figure 1c) and the provision of high-resolution, global images of chlorophyll on a daily basis led to step changes in our understanding of, for example, physical–biological interactions, mesoscale processes and the effect of climate oscillations, such as El Niño–La Niña (see [22] for a review). Each of these daily satellite chlorophyll images contains approximately 3 million non-cloudy pixels, i.e. we are now acquiring 10 times more chlorophyll measurements every day than were obtained in the entire 200 years prior to the advent of ocean colour satellites.Figure 1.

RSTA20130334F1: (a) Density of in situ surface chlorophyll concentration measurements collected between 1773 and 1997, extracted from the World Ocean Database at http://www.nodc.noaa.gov/OC5/SELECT/dbsearch/dbsearch.html; data collected from time-series stations, shipboard profiles and under-way systems, and gliders. (b) In situ chlorophyll concentration from the top 10 m collected at the Hawaii Ocean Time-series site every two to four weeks between 1989 and 2012; acquired from http://hahana.soest.hawaii.edu/hot/hot-dogs/. (c) Global chlorophyll concentration (mg m−3) at 9 km spatial resolution averaged between April and June 1998 acquired by the SeaWiFS satellite; data downloaded from http://oceancolor.gsfc.nasa.gov/. (Online version in colour.)

Mentions:
In the past 30 years or so, SOs have wrought a revolution in biological oceanography. To put this into perspective, I present an example based on chlorophyll concentration. Between 1773 and 1997, chlorophyll was measured in situ at a total of approximately 300 000 stations (as reported in the World Ocean Database). Although this is a huge number of data points, inspection of the data distribution in figure 1a shows that large parts of the ocean have less than five measurements and some have none at all. Vast tracts of the Southern Ocean, for example, have zero or only one data point in the database. It would be difficult to ascertain even the broad-scale distribution of chlorophyll concentration from this dataset, and one would struggle to deduce any information on temporal variability on the large scale. The advent of regular sampling at SO locations began to reveal detailed information about the seasonal (and eventually interannual) variability in chlorophyll concentration, as shown in the example for the Hawaii Ocean Time-series site (HOT; figure 1b). Information on the temporal variability of chlorophyll allowed significant advances in our understanding of the range of variability and the physical and biological factors that control chlorophyll concentrations. However, time-series station data cannot provide any information on the spatial variability in chlorophyll, except at the largest scales (e.g. the differences between ocean basins through a comparison of HOT and the Bermuda Atlantic Time-series Study site; BATS). The arrival of satellite-derived chlorophyll data in the late 1970s prompted another revolution in biological oceanography as the dramatic spatial variability in chlorophyll on mesoscales was revealed (figure 1c) and the provision of high-resolution, global images of chlorophyll on a daily basis led to step changes in our understanding of, for example, physical–biological interactions, mesoscale processes and the effect of climate oscillations, such as El Niño–La Niña (see [22] for a review). Each of these daily satellite chlorophyll images contains approximately 3 million non-cloudy pixels, i.e. we are now acquiring 10 times more chlorophyll measurements every day than were obtained in the entire 200 years prior to the advent of ocean colour satellites.Figure 1.

Bottom Line:
Here, I highlight some of the key breakthroughs in biological oceanography that have been enabled by SOs, which include areas such as trophic dynamics, understanding variability, improved biogeochemical models and the role of ocean biology in the global carbon cycle.In the near future, SOs are poised to make progress on several fronts, including detecting climate change effects on ocean biogeochemistry, high-resolution observations of physical-biological interactions and greater observational capability in both the mesopelagic zone and harsh environments, such as the Arctic.We are now entering a new era for biological SOs, one in which our motivations have evolved from the need to acquire basic understanding of the ocean's state and variability, to a need to understand ocean biogeochemistry in the context of increasing pressure in the form of climate change, overfishing and eutrophication.

ABSTRACTSustained observations (SOs) have provided invaluable information on the ocean's biology and biogeochemistry for over 50 years. They continue to play a vital role in elucidating the functioning of the marine ecosystem, particularly in the light of ongoing climate change. Repeated, consistent observations have provided the opportunity to resolve temporal and/or spatial variability in ocean biogeochemistry, which has driven exploration of the factors controlling biological parameters and processes. Here, I highlight some of the key breakthroughs in biological oceanography that have been enabled by SOs, which include areas such as trophic dynamics, understanding variability, improved biogeochemical models and the role of ocean biology in the global carbon cycle. In the near future, SOs are poised to make progress on several fronts, including detecting climate change effects on ocean biogeochemistry, high-resolution observations of physical-biological interactions and greater observational capability in both the mesopelagic zone and harsh environments, such as the Arctic. We are now entering a new era for biological SOs, one in which our motivations have evolved from the need to acquire basic understanding of the ocean's state and variability, to a need to understand ocean biogeochemistry in the context of increasing pressure in the form of climate change, overfishing and eutrophication.